In today's world, some articles of clothing are specifically designed for extreme physical activities that place great duress on hand-tied knots, such as board shorts for surfing and athletic shoes worn on the field or court of play. Extreme physical activities such as these often disengage the knots tied in laces, causing the articles of clothing to loosen on the wearer's body, often at very inopportune times.
Articles for use in assisting the tying or securing of laces, in addition to or in lieu of hand-tied knots, are not uncommon. Typically, these articles are bulky and uncomfortable to the wearer, are easily broken, or are ineffective altogether at holding laces securely in more stressful environments. For some laces and applications in which they're used, even just tying the laces in a knot without using a tying/securing device of any sort can make the laces bulky and uncomfortable to the wearer.
Many of the devices designed to hold laces in place or to knot the laces are made of hard, brittle plastics and have moving parts that are unreliable. One such device that is commonly available is the spring-loaded clasp, such as that shown in U.S. Pat. No. 7,152,285. Spring-loaded clasps are highly effective for some uses, but they are prone to breaking after repeated use or when used in more extreme physical activities. Also, even though they are very simple mechanical devices, spring-loaded clasps are relatively expensive to manufacture (compared to other much simpler devices) and are difficult to replace once broken, as they typically come pre-installed with the laces they are meant to secure and are not readily available as individual units to be used as replacement parts.
The notched disk of U.S. Pat. No. 9,347,522 is an example of a very simple, inexpensive lace-securing device that offers two different options (most useful when applied in combination) for securing laces, each option requiring manufacture from materials that are both rigid and compressible at the same time, such as the highly dense polyurethane foam or hard plastic materials described in the '522 patent. With this device, the user inserts the laces through a hole in the device and then secures them by inserting them into two slits formed along the edges of the device. Using a highly dense but slightly compressible material allows the laces to slide into the slits and then, for a time, be held in place by the compressing forces of the material. The other technique for using this device is simply to insert the laces through the hole and leave the laces hanging there, a technique that works only when the laces are of sufficient thickness to compress the material around the hole significantly. With both of these techniques, however, the device of the '522 patent is prone to losing its grip on the laces over time, especially when used in high-impact activities, such as surfing and highly active sports like basketball and distance running